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I got the 6.2 blues

RNation

RNation

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St.Peters, MO
Hello all, I'm new to here and diesel engines. But I have a 84 Suburban with the 6.2 in it. I've ran into a couple issues with it, first I found oil in radiator but no water in oil. Took the heads off (before I found out there's an oil cooler integrated into radiator, which I ended up replacing) and had them checked out, the guy magnufluxed them and said there was a few small cracks that didn't mean anything (he didn't mill them which I found out later was very important to do so). So I put them back on and got everything torqued right etc. Now I have a lot of oil in cooling system and found some moisture on dipstick. So I'm at a point of confusion. Should I get new heads and hope the blocks not cracked or just get a rebuilt short/long block? There's around 160,000 miles so I thought the block should be ok, but the temp gauge was broke when I bought it and I never really paid any attention to it, so I'm not sure how hot it got. Any info. would be greatly appreciated.
 
Plug the oil cooler temporarily and see if that fixes your problem. Some small cracks are normal. Cracks into the combustion chambers and coolant passages are bad. Did you replace the headbolts with new ones ? They are not resuable and are wet and need sealanyt on them(New ones come pre coated). Studs are the preferred method with intruck head jobs as TTY bolts can't really be properly torqued in vehichle. I would take the oil cooler out of the loop and flush the system and see what you have before ripping the engine apart again. The in rad oil coolers were troublesome and that is why GM later got rid of them on the Newer trucks. If not the Oil cooler sounds like a botched(sorry to put it that way) HG job. It could be the headbolts.
 
Thanks for the quick reply. As far as the oil cooler goes I have got a new radiator. So I believe the oil cooler should be able to be ruled out or do you mean even a new one could be troublesome? With the heads I did use new bolts but the heads weren't milled which is bad right? The cracks were in between valve holes. The studs your talking about, are they more reliable for torquing down?

On another note, some local mechanic had said his friend has some blueprints for the motor and said the only places the oil and coolant cross in in radiator, lifter bores, and i think behind water pump. I'm not sure if that's right or not though. I guess I'm trying to determine if the blocks bad or not without spending to much more money.

Thanks again
 
Water could easily leak into the motor through the Headbolts. They go into the water jacket. Studs are much better. I'm sorry I didn't use them but I didn't quite understand that they can be installed like bolts and I couldn't see at the time how I'd get the head on in the truck. I now know better. I'll never use bolts again. If you are getting alot of water in the oil It may be worth pulling the valve covers and then pressurizing the system to see if it's leaking past the bolts. There are obviously more catastrophic things it could be but since you didn;'t have water in the oil before you pulled the heads I'd be kind of inclined to check that. Heck if it was one bolt leaking I'd even just pull that bolt, Put sealer on it and reinstall. I wouldn't be so quick to blame the heads because you did the right thing and had them checked. Cracks between the valves is normal on these. I would probablly take the valve covers off(I know PIA) and pressurize it. If you don't find anything that way the next step would probably be to pull the oil pan and pressurize. A cracked cylinder can cause this as well.
 
OK i'll give that a try. How do I go about pressurizing the system (not sure what PIA means). Are you talking about doing a pressure check where I pull out the glow plugs and and hook up compression tester or is this a different method that your talking about.

Sorry for all the questions, I'm just a drywaller, not much of a mechanic at all, i'm trying to learn this all as I go.
 
PIA= Pain in the A...
Pressurizing is done with a tool. You can buy them from Harbor frieght cheap enough. It looks like a handpump that hooks up to your radiator cap. Called a cooling system pressure tester IIRC.
 
Basically pull the VC's and the put this tool on the rad and pump to 20 lbs or so and hopefully you see coolant pissing out of somewhere. The only time it's a PIA is when it's a crack somewhere that shows itself only when hot. I suppose you could plug in the block heater. I just got a gut feeling from what you are describing that a bolt is leaking. The new Headbolts you used, wer they coated with sealant ? Also TTY Bolts are near impossible to properly torque in truck as I found out the hard way. I would also have the glowplugs out when you do this so although if it's in the oil probably won't see it coming from a cyl. How much water is in the oil ? I mean if you drain the oil are you getting ALOT of water or do you just have peanut butter for oil ? If you drain it and a huge amount of pure coolant comes out, that is usually a really bad sign.
 
PIA = PITA = Pain In The A** = :cuss:

Correct me if I'm wrong here, but since the original prob was oil in the radiator, seems unlikely that oil would be seeping through the head bolt threads and contaminating the coolant, more likely the other way around, no?

And since now he's got more oil in the water than before, and now some water in the oil as well, it really doesn't sound good. Where else would you have high oil pressure and low(er) coolant pressure aside from the cooler in the rad tank?

Just trying to think what else it could possibly be aside from a cracked block...
 
well the way I read it was he had a bad oil cooler but thought he had bad HG's so he pulled the heads. He has since replaced the rad/oil cooler which I assume was confirmed bad so I "think" he created the new problem. In any case I think pressurizing it will hopefully tell the tale. You could also unhook one of the oil cooler lines at the rad while doing your pressure test to see if you get pressure there. I suppose it's possible you got a bad rad. Can never rule anything out until the problem is found.Maybe you should try that first before you pull the VC's.
 
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Remember, his new symptom is getting water INTO the oil as well so I think pressurizing it with the VC's off is the place to start if the oil cooler has no pressure with tester on. If nothing shows up there then pulling the Oil pan unfortunatley is next. Hopefully your working on an OBS truck. You have no signature.
 
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The more I think about it Redshift is right. I would defintely pull the Oil cooler lines off and pressurize the rad before I did anything else. That is the easiest. You did flush the block right ? It would not be funny to rip stuff apart when all it was , was residual from the original problem. Did you change the oil after putting the heads back on ? I know that sounds obviously stupid but gotta ask.
 
The new head bolts were dipped in some kind of orange liquid witch i suppose is the sealant. And yes my original problem was alot of oil in radiator (not sure if it built up over time or not). I replaced HG because people were telling me it was probably bad heads or HG or block. I found out half way through my truck has an oil cooler. Put heads back on (they weren't milled which i think is bad). No I have alot of oil in radiator (I did flush as much oil out as possible before starting truck after heads were installed) and some moisture on the dipstick. So i'm not sure exactly how much water is in oil, I haven't checked yet because I was unsure what to do next. Also old radiator was never confirmed to be problem, i had it checked and it was good but they said test wasn't 100 percent because they dont check the radiator while its hot.
 
I didn't flush the block because I don't know how, I just flushed the cooling system the best I could w/ out radiator. I put a hose in the thermostat housing and ran for a while and put some cascade dish soap in there to help, I thought that would flush the block alittle bit but not sure
 
and I changed the oil right before I took the heads off, actually thats how I found the original proble was when I was changing oil and checking coolant and I discovered oil in radiator
 
RNation said:
I didn't flush the block because I don't know how, I just flushed the cooling system the best I could w/ out radiator. I put a hose in the thermostat housing and ran for a while and put some cascade dish soap in there to help, I thought that would flush the block alittle bit but not sure
Click to expand...

That is what I meant.
 
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